High impact information on ras1

• Additional experiments demonstrate that this cAMP signaling pathway is independent of the S. pombe ras1 gene and works by activation of cAMP-dependent protein kinase [1].
• A novel suppressor of ras1 in fission yeast, byr4, is a dosage-dependent inhibitor of cytokinesis [2].
• From a gene library, we have isolated a gene, byr1+, which when in high copy number restores efficient sporulation to ras1- strains. byr1+ encodes a putative 340-amino acid protein product, the sequence of which strongly suggests that it functions as a protein kinase [3].
• In the fission yeast Schizosaccharomyces pombe, ras1 regulates both sexual development (conjugation and sporulation) and cellular morphology [4].
• This phenotype was similar to phenotypes of cells bearing an activated allele of ras1, such as ras1Val-17 or ras1Leu-66, and phenotypes of cells defective in gap1 [5].

Biological context of ras1

• A novel gene, designated byr4, was identified in Schizosaccharomyces pombe that affects the mitotic cell cycle and shows genetic interactions with the ras1 signaling pathways [2].
• Schizosaccharomyces pombe ras1 and byr1 are functionally related genes of the ste family that affect starvation-induced transcription of mating-type genes [6].
• These observations provide a molecular basis for the role of the ste gene family, including ras1 and byr1, in meiosis and indicate that further characterization of other ste genes would be very useful for elucidating the mechanism of ras1 function in fission yeast cells [6].
• byr2, a Schizosaccharomyces pombe gene encoding a protein kinase capable of partial suppression of the ras1 mutant phenotype [7].
• Two types of dominant interfering mutants were isolated in a genetic screen for ras1 mutants that blocked sexual development [4].

Anatomical context of ras1

• Among low-molar-mass species, a component moving as a band at 31 kDa was conspicuous in ras1- cell walls [8].

Regulatory relationships of ras1

• By Northern analysis of RNA preparations from strains carrying wild-type or mutant ras1 alleles and grown to different stages of the growth cycle, we have shown that ras1 plays an important role in inducing the Pi transcript of the mating-type loci and the mei3 gene transcript [6].

Other interactions of ras1

• Several physiological similarities between strains containing null alleles of these genes supports the idea that ras1 and byr1 are functionally closely related [6].
• Characterization of the Schizosaccharomyces pombe ral2 gene implicated in activation of the ras1 gene product [9].
• The ste6 gene of Schizosaccharomyces pombe encodes a putative GDP-GTP exchange factor for the ras1 gene product [10].

References